2.0 FACILITIES /REQUIREMENT
- A sizeable parcel of land easily accessible of at least 2000m2
- Number of gauge steel moulds; for 8.54 and 10.36m, minimum of 10 respectively and 5 for 12.20m
- The design specifications for the reinforced or pre-stressed electric concrete poles with relevant design drawings;
- Well prepared concrete casting/moulding bay (concrete floor area);
- At least two (2) numbers of industrial concrete mixing machines;
- At least two (2) numbers of industrial vibrators;
- Supply the following for the company’s manufactured reinforced or pre-stressed electric concrete poles;
- Detailed Structural design of the Pole
- Isometric view
- A COREN certified supervising Engineer (civil/structural engineer)
- Experience Iron benders in addition to other production personnel;
- Adequate mechanical working tools
- Adequate water supply facilities preferably a borehole;
- A well-prepared Testing Rig with associated pull winch and a good dial gauge of at least 2500kN/Kg range
- For pre-stressed types, the right equipment and facilities must be available on Factory or Production site.
- Curing ponds of appropriate size capable of handling 10 & 15 numbers of poles at a time must be provided at the factory or production site.
- Means of lifting poles in the curing ponds and out of the curing ponds without causing any damage to the pole
- Aggregate: shall be graded crushed stones of 12.50mm maximum size and shall be tested in an accredited laboratory.
- Concrete: For Ordinary Portland Cement, the mix proportion of the constituents shall be any designed mix and shall have minimum works cube strength of 37N/mm2 at 28 days
- Concrete cover: the minimum cover to all reinforcement shall be 25mm.
- Steel reinforcement: the longitudinal reinforcement bars shall be 12/10mm diameter high yield steel as may be specified in the approved and authorized design/details.
- The stirrups shall be 6mm diameter mild steel as may be specified in the approved and authorized design/details
- Longitudinal dimension shall not deviate from the nominal design dimension by more than 25mm.
- Location of the holes shall not deviate more than 1mm from the nominal design dimensions
- The hole spacing shall not deviate more than 3mm from nominal design dimension.
- For 12.20m (special pole), the design specification is as described in the annexure
- Cross sectional dimension shall not deviate from design dimension of 6mm.
- The planting depth of the pole shall not be less than one sixth of the total length of the pole above ground level and shall not be less than 1.5 m.
- All manufactured electric concrete poles must have the batch number on the pole and the date of production recorded in a production log
- All manufactured electric concrete poles shall have provision for concealing earthing wires that will prevent pilferage by vandals.
- All materials used in the manufacture of electric concrete poles must conform to Nigerian Industrial Standard (NIS)
- The electric concrete poles manufacturers are also expected to acquire MANCAP of Standards Organization of Nigeria (SON).
3.0 Minimum ultimate Transverse Head Load (kg) for high- and low-tension poles are shown below
|S/N||Class of Poles
|Minimum Ultimate Transverse Head loads at 600mm from Top (kg)|
|i.||0.415||8.54 (Low Tension)||400|
|ii.||11||10.36 (High Tension)||600|
|iii.||33||10.36 (Special Pole)||600|
|iv.||33||12.20 (Special Pole)||600|
Source: Standards Organization of Nigeria (SON) NIS 586:2007